Configuring /etc/hosts
======================

By default, TPA adds lines to ``/etc/hosts`` on the target instances
with the IP address and hostnames of every instance in the cluster. This
enables the instances to use each other’s names for communication within
the cluster (for example, in ``primary_conninfo`` for Postgres).

You can specify a list of ``extra_etc_hosts_lines`` , too:

.. code:: yaml

   instances:

   - Name: one
     …
     vars:
       extra_etc_hosts_lines:
       - 192.0.2.1 acid.example.com
       - 192.0.2.2 water.example.com

If you don’t want any of the default entries, you can specify the
complete list of ``etc_hosts_lines`` for an instance instead. Add only
those lines to ``/etc/hosts`` :

.. code:: yaml

   instances:

   - Name: one
     …
     vars:
       etc_hosts_lines:
       - 192.0.2.1 acid.example.com
       - 192.0.2.2 water.example.com
       - 192.0.2.3 base.example.com

If your ``/etc/hosts`` doesn’t contain the default entries for instances
in the cluster, you need to ensure the names can be resolved in some
other way.